The Pennsylvania Turnpike is one of the best-known highways in the United States. Most Pennsylvania Turnpike travelers are unaware that its construction was inspired by the route of the never completed South Pennsylvania Railroad. In the 1930s, men of great vision conceived, planned, and built the nation's first long-distance superhighway using the abandoned railroad's partially finished tunnels as its foundation. Originally predicted to be a financial failure, the project was a tremendous success, and the turnpike came to be known as the World's Greatest Highway. Over the years, the Pennsylvania Turnpike was expanded and improved, laying the groundwork for the nation's Interstate Highway System. The Pennsylvania Turnpike draws from the extensive photograph collection in the Pennsylvania State Archives. Many were taken by photographers hired by both the Pennsylvania Turnpike Commission and its contractors, and most have never been published previously.

Mitchell E. Dakelman is director of media services for the National Railroad Historical Society. He is an avid collector of transportation photographs, motion pictures, and memorabilia. Neal A. Schorr is a physician in suburban Pittsburgh with a lifelong interest in highway engineering. He designed the plan for widening Pittsburgh's worst traffic bottleneck, the Fort Pitt Bridge and Tunnel.